Cereal grinding mill



June 4, 1940. E. e. BERRY ET AL CEREAL GRINDING MILL Filed Jan. 21, 1938 2 Sheets-Sheet 1 June 4, 1940. BERRY AL 2,202,892

CEREAL GRINDING MILL Filed Jan. 21, 1938 2 Sheets-Sheet 2 I40 eye 6 LB??? m %& I

Patented June 4, 1940 UNITED STATES PATENT OFFICE CEREAL GRINDING MILL Application January 21, 1938, Serial No. 186,047

1 Claim.

This invention relates to a cereal grinding mill primarily adapted for grinding coffee, but susceptible for grinding or granulating various products.

The invention is directed more particularly to the grinding means which consists of corrugated rolls which are arranged in pairs.

In the past, it has been common to use a first reduction or breaker means and a second or final reduction or granulating means. The first reduction means consisted of a roller and a toothed breaker bar, or a pair of cooperating corrugated rolls. The second or final reduction means consisted of a pair of corrugated rolls comprising a fast and a slow roll. In order to increase the supply of material furnished to the final reduction rolls, a second set of first reduction or breaker means has been used in some instances, providing thereby a triple reduction mill. This triple reduction process increased the size, especially the height of the mill, and also increased the cost thereof.

It is accordingly an object of this invention to increase the capacity of such a mill or to obtain the capacity of a triple reduction mill in a mill having only two sets of grinding elements, namely, a set of breaker rolls and a set of granulating or finishing rolls.

In order to accomplish the foregoing stated object, an improved first reduction means has been provided that produces the desired increased capacity in connection with the final reduction rolls. To this end, the first reduction rolls are corrugated both longitudinally and. circumferentially in a particular manner, and the teeth are made to slope circumferentially in opposite directions.

The invention comprises the novel structure and combination of parts hereinafter described and more particularly pointed out and defined in the appended claim.

In the accompanying drawings which illustrate a preferred form of this invention and in which similar reference characters refer to similar features in the different views:

Figure 1 is a rear elevational view of a coffee mill involving this invention;

Figure 2 is an enlarged sectional view through the same;

Figure 3 is an enlarged fragmentary side elevational view of the first reduction rolls involving this invention;

Figure 4 is an enlarged fragmentary top plan view of the first reduction rolls;

Figure 5 is a fragmentary sectional View taken substantially upon the line VV of Figure 3;

Figure 6 is a fragmentary sectional view taken substantially upon the line VI--VI of Figure 5.

In order to illustrate an application of this invention, there is shown in the drawings a roller mill primarily designed for granulating coffee and consisting of a casing I having a pair of reduction rolls 2 and 3 journaled therein, and below these reduction rolls are a pair of final reduction rolls 4 and 5 which are preferably provided with what is known as the Le Page corrugations.

The rolls 2 and 4 are rotated at faster speeds. than the rolls 3 and 5 and will herein be termed the fast rolls, while the rolls 3 and 5 will. be termed the slow rolls.

At the bottom of the casing, there is a motor 6, the shaft 1 of which carries a sprocket gear 8 around which there is trained a sprocket chain 9. This sprocket chain 9 is also trained over a sprocket gear I!) on the shaft II that carries the fast roll 4.

Upon the bottom of the casing I, there is attached a chaff comminuting cylinder l2, from which there extends a conveyor shaft I3 that supports a sprocket gear M. The shaft l5 that supports the slow roll 5 carries a sprocket gear I6. The shaft ll carries a small sprocket gear l1, and at the side of the casing there is mounted an idler sprocket gear 18, a sprocket chain i9 is trained over the sprocket gears M, l6, l8 and I1, and is caused to rotate through the rotation of the shaft II by the sprocket chain 9. Due to the fact that the sprocket gear I6 is much larger than the sprocket gear H, the shafts l5 and II that support said sprockets will rotate at different speeds. The shaft l5 that carries the slow roll 5 will rotate at a much slower speed than the shaft II that carries the fast roll.

The shaft ll supports a second small sprocket gear hidden from view, and the shaft 20 that carries the fast breaker roll 2 carries a sprocket gear 2|. A sprocket chain 22 connects the hidden sprocket gear and the sprocket gear -2|. Likewise, the shaft [5 carries a small sprocket gear 23, and the shaft 24 that carries the slow breaker roll 3 supports a sprocket gear 25. A sprocket chain 26 is trained over the sprocket gears 23 and 25. It will be noted that the sprocket gears 2| and 25 are substantially the same size, and that the sprocket gears I1 and 23 are substantially of the same size but smaller than the sprocket gears 2| and 25.

Thus it will be apparent that the breaker rolls 2 and 3 rotate at different speeds and that the roll 3 travels at the slower speed. The ratio between the speeds of the breaker rolls is substantially the same ratio as exists between the speeds of the granulating rolls 4 and 5. The latter, however, rotate much faster than the breaker rolls.

Referring now to Figures 3 to 6, which illustrate the breaker rolls, it will be noted that these rolls are corrugated circumferentlally as well as lengthwise. The rolls 2 and 3 are formed with U-shaped grooves 2'! extending in a circumferential direction and with longitudinally extending grooves or corrugations 28 that are rounded or U-shaped at the bottom, as indicated at 29, whereby pyramidal teeth are formed.

It will, however, be noted that the horizontal grooves 28 in the rolls are reversely arranged. The grooves 28 in the fast roll 2 are cut to provide teeth 39, each having curved sides or faces 3| and 32. The teeth as slope forwardly in the direction of rotation of the roll.

The grooves or corrugations 28 in the slow roll 3 are cut to provide teeth 33, each having curved sides or faces 34 and 35. The teeth 33 slope rearwardly or in a direction contrary to the direction of rotation of the roll.

In referring to Figure 3, it will be seen that the fast roll 2 rotates in a counter-clockwise direction, while the slow roll 3 rotates in a clockwise direction causing the adjacent portions of the rolls to move downwardly in the same direction at different speeds. The arrangement is such that the pyramidal teeth 30 of the fast roll extend into the U-shaped grooves 2'? of the fast roll.

With the arrangement as shown, the kernels or coffee beans that are fed between the breaker rolls are easily and quickly gripped between the teeth without any tendency for them to spring upwardly, for it is evident that the kernels or beans will readily slip down the curved faces of the teeth 33 of the slow roll and be gripped by the teeth of the fast roll. As the teeth of the fast roll move past the teeth on the slow roll, a relative movement therebetween is produced that causes a crushing or breaking action with respect to the beans or kernels, as shown in Figure 3.

t has been found in actual practice that the breaker rolls above described will do the Work of two sets of breaker rolls and combs heretofore used. This increased capacity is largely due to the fact that the arrangement of the teeth of the rolls act more effectively as ieecfing elements to draw the beans or kernels down between the rolls. The U-shaped grooves 21 and 28 provide increased spaces to accommodate the amount of material drawn in by the rolls without causing any jamming action. The pyramidal teeth will readily reduce the amount fed therebetween, due to the increased feeding action thereof.

It will be appreciated that the results accomplished by this invention are exceedingly important from the standpoint of economy and emciency. The invention not only simplifies the prior machines in use, but it also reduces the grinding elements of the prior art machines Without decreasing the capacity or efficiency thereof.

We are aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and we, therefore, do not purpose limiting the patent granted hereon otherwise than is necessitated by the prior art.

We claim as our invention:

A pair of cooperating rolls for reducing material, each of said rolls having circumferentially extending U-shaped substantially symmetrical grooves with their adjacent walls cooperating to form sharp edged portions between the grooves, the rolls being disposed with the sharp edged portions on one roll extending into and substantially central of the grooves of the other roll, circumferentially spaced round bottomed grooves extending longitudinally of each roll, each of said latter grooves having a curved wall and an inclined substantially flat surfaced wall, the flat walls in one of said rolls being inclined in its direction of rotation and in the other roll in a reversed direction, said circumferenti'ally and. longitudinally extending grooves cooperating to form pyramidal teeth inclined in opposite directions and having pointed apices.

EUGENE G. BERRY. WILLIAM IVI. WILLIAMS. 

